The invention relates to a process for producing multilayered articles from a polymer melt, in particular in an injection mold, in particular from preforms, with a barrier layer.
U.S. Pat. No. 8,329,075 describes in principle a process for monitoring, documenting and/or controlling an injection-molding machine with an injection mold, into which a melt is introduced, a viscosity of the melt in the injection mold being determined directly. In this case, the determination of the viscosity is performed by using the respective quotients of shear stress and shear rate on the basis of pressure differences, the geometry of the cavity and the flow rate of the melt. Sensors for the internal pressure of the mold or sensors for the wall temperature of the mold could be used, for example, for the determination.
The problem addressed by the present invention is that of making the basic concept that is described in U.S. Pat. No. 8,329,075 accessible for further processes and applications.